1. Field of the Invention
The present invention relates to a catheter with an ultrasound assembly, and more particularly, to a catheter with an ultrasound assembly which reduces the exposure of at least one lumen within the catheter to ultrasound energy.
2. Description of Related Art
It is frequently desirable to use a catheter to deliver various media to treatment sites within the body. The delivered media frequently includes drugs, medicaments, microbubbles and other therapeutically beneficial compounds. For instance, catheters are frequently used to treat thrombi which have formed in the cardiovascular vessels of the body. These catheters are used to deliver solutions containing dissolution compounds directly to the thrombus. Many catheters include an ultrasound transducer for delivering ultrasound energy to media which has been delivered to the treatment site. The ultrasound energy in combination with the delivered media and/or the ultrasound energy can enhance the desired therapeutic effects.
The media are typically delivered to the treatment site through lumens in the catheter. These lumens frequently must pass near the ultrasound transducer. As a result, the media can be exposed to the ultrasound energy before the media is delivered to the treatment site. This exposure can reduce the therapeutic effect of the media. For instance, when the delivered media is microbubbles, the microbubbles can be burst within the lumen before the microbubbles are delivered. The therapeutic effect from microbubbles can be a result of the microbubbles bursting after delivery to the treatment site. Bursting the microbubbles before they are delivered to the treatment site can deprive the treatment site of this therapeutic effect.
Many catheters suitable for the delivery of media and microbubbles are frequently positioned within a patient using over he-guidewire placement techniques. When these techniques are used, it is frequently desirable to leave the guidewire within a catheter during the delivery of the media and the ultrasound energy. However, the presence of the guidewire within the catheter can alter the frequency of the ultrasound energy produced by the ultrasound transducer. As a result, the frequency of the ultrasound energy actually produced by the ultrasound transducer may be different than the desired frequency.
There is a need for a catheter including an ultrasound assembly which reduces the exposure of lumens within the catheter to ultrasound energy delivered from the ultrasound transducer.